JP2013248897A - Motion control device of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motion control device of a vehicle which can prevent the overheating of an electric motor and can keep long the continuous execution time of automatic pressurization control.SOLUTION: A motion control device 50 reduces a pressure increase gradient of wheel cylinder hydraulic pressure generated through automatic pressurization control when a motor temperature T of an electric motor M reaches a referential temperature Tb or higher. Thereby, the consumption of accumulator hydraulic pressure Pa can be suppressed to reduce a driving amount (a load and driving time) of a hydraulic pump HP, namely, the electric motor M, by the suppressed amount. As a result, the overheating of the electric motor M can be prevented to improve the durability of the electric motor M. The reliability of braking can be also enhanced by keeping long the continuous execution time of automatic pressurization control.

Description

  The present invention relates to a vehicle motion control device that controls a braking force by adjusting an accumulator hydraulic pressure that is a pressure of a brake fluid stored in an accumulator.

  In a vehicle motion control device, a hydraulic pump is driven by an electric motor so that an accumulator hydraulic pressure of an accumulator that is a high-pressure source is maintained at a predetermined pressure or higher. In this vehicle motion control device, for example, in addition to braking based on the driver's operation, if braking is performed by automatic pressurization control (automatic brake control) unrelated to the operation, the consumption of accumulator hydraulic pressure Increases, the drive amount (load and drive time) of the electric motor increases, and the electric motor may overheat. Since overheating of the electric motor can cause a decrease in the durability of the motor, for example, in Patent Document 1, when the motor temperature of the electric motor exceeds a predetermined temperature, the driving of the electric motor is stopped and the electric motor is stopped. An apparatus for preventing overheating is described.

JP 2009-19462 A

  If the braking by the automatic pressurization control is performed in the state where the driving of the electric motor is stopped, the accumulator hydraulic pressure is only consumed and it tends to be insufficient. In this case, inconveniences such as shortening the continuous execution time of the automatic pressurization control tend to occur.

  The present invention has been made in view of such circumstances, and provides a vehicle motion control device that can prevent overheating of an electric motor and can keep a continuous execution time of automatic pressurization control long. The purpose is to do.

  The invention according to claim 1 controls the pressure adjusting means for adjusting the wheel cylinder hydraulic pressure, which is the brake hydraulic pressure in the wheel cylinder of the wheel brake, the hydraulic pump, and the electric motor that drives the hydraulic pump. Drive control means, accumulator for storing brake fluid boosted by driving the hydraulic pump by the electric motor, and detection means for detecting accumulator fluid pressure that is the pressure of the brake fluid stored in the accumulator And automatic pressurization control means for performing automatic pressurization control for generating the wheel cylinder hydraulic pressure independently of a brake operation by a driver by controlling the pressure adjusting means using the accumulator hydraulic pressure, Motor temperature deriving means for deriving the temperature of the electric motor, and when the temperature of the electric motor is equal to or higher than a predetermined temperature, And boost control means for reducing the boost gradient of the wheel cylinder hydraulic pressure generated by the pressurization control is that with the.

  According to a second aspect of the present invention, in the first aspect, when the accumulator hydraulic pressure detected by the detection unit is less than a predetermined hydraulic pressure, the boost control unit reduces the pressure gradient of the wheel cylinder hydraulic pressure. It is.

  A third aspect of the present invention is the method according to the first or second aspect, wherein the step-up control means changes the degree of decrease in the pressure-increasing gradient of the wheel cylinder hydraulic pressure in accordance with the temperature increase rate of the electric motor. .

  According to a fourth aspect of the present invention, in the third aspect, the step-up control means reduces the degree of decrease in the pressure-up gradient of the wheel cylinder hydraulic pressure as the temperature increase rate of the electric motor decreases.

  According to the first aspect of the present invention, when the motor temperature of the electric motor is equal to or higher than the predetermined temperature, the pressure increase control means reduces the pressure increase gradient of the wheel cylinder hydraulic pressure generated by the automatic pressure control. Thereby, consumption of the accumulator hydraulic pressure can be suppressed, and the driving amount (load or driving time) of the hydraulic pump, that is, the electric motor can be reduced by the suppression amount. Therefore, overheating of the electric motor can be prevented and the durability of the electric motor can be improved. And the continuous execution time of automatic pressurization control can be kept long, and the reliability of braking can be improved.

  According to the second aspect of the present invention, the pressure increase control means reduces the pressure increase gradient of the wheel cylinder hydraulic pressure when the accumulator hydraulic pressure is less than the predetermined hydraulic pressure. As a result, when the accumulator hydraulic pressure is equal to or higher than the predetermined hydraulic pressure, the pressure is returned to the normal pressure increase gradient. Therefore, the pressure increase time of the wheel cylinder hydraulic pressure can be shortened, and the braking response can be improved. .

  According to the third aspect of the present invention, the pressure increase control means changes the degree of decrease in the pressure increase gradient of the wheel cylinder hydraulic pressure in accordance with the speed of increase of the motor temperature of the electric motor. Even if it is fast, the degree of decrease in the pressure gradient of the wheel cylinder hydraulic pressure can be increased, that is, the pressure increase gradient can be reduced to suppress the consumption of the accumulator hydraulic pressure. Therefore, the drive amount (load or operation time) of the electric motor can be reduced, and overheating of the electric motor can be reliably prevented.

  According to the fourth aspect of the present invention, the pressure increase control means reduces the decrease degree of the pressure increase gradient of the wheel cylinder hydraulic pressure as the motor temperature increase rate of the electric motor decreases. Boosting time can be shortened.

1 is a diagram showing a schematic configuration of a vehicle equipped with a brake device including a vehicle motion control device according to an embodiment of the present invention. It is a schematic block diagram of the brake fluid pressure control apparatus of FIG. It is a flowchart for demonstrating the automatic pressurization control operation which the motion control apparatus of FIG. 1 performs. (A), (b), (c), (d) and (e) show changes in accumulator hydraulic pressure, electric motor operation, motor temperature, boost control and wheel cylinder hydraulic pressure in the automatic pressurization control of FIG. It is a time chart which shows. It is a flowchart for demonstrating another automatic pressurization control operation which the motion control apparatus of FIG. 1 performs. (A), (b), (c), (d) and (e) show changes in accumulator hydraulic pressure, electric motor operation, motor temperature, boost control and wheel cylinder hydraulic pressure in the automatic pressurization control of FIG. It is a time chart which shows. It is a schematic block diagram of another example of the brake fluid pressure control apparatus of FIG.

  Embodiments of a vehicle motion control apparatus according to the present invention will be described below with reference to the drawings. As shown in FIG. 1, this vehicle is a front wheel drive type vehicle in which the two front wheels are drive wheels. The brake device 10 including the vehicle motion control device generates a driving force and transmits the driving force to the driving wheels FL and FR, and the wheels FL, FR, RL, and RR. A brake fluid pressure control device 30 for generating a braking force by the brake fluid pressure, a sensor unit 40 composed of various sensors and the like, a motion control device 50 ("drive control means" of the present invention, "automatic pressure control") Means ”,“ motor temperature deriving means ”,“ boosting control means ”), and the like.

  The driving force transmission mechanism unit 20 is arranged in an engine 21 that generates a driving force, and a DC that is disposed in the intake pipe 21a of the engine 21 and controls the opening of a throttle valve TH that makes the opening cross-sectional area of the intake passage variable. A throttle valve actuator 22 composed of a motor and a fuel injection device 23 including an injector for injecting fuel in the vicinity of an intake port (not shown) of the engine 21 are provided.

  Further, the driving force transmission mechanism unit 20 is connected to the output shaft of the engine 21 with the input shaft connected thereto, and is connected to the output shaft of the transmission 24 to appropriately distribute the driving force of the engine 21 so that the front wheels FL, FR And a front wheel side differential 25 and the like for transmitting to the front.

  As shown in FIGS. 1 and 2, the brake fluid pressure control device 30 includes a high pressure generator 31, a brake fluid pressure generator 32 that generates brake fluid pressure according to the operating force of the brake pedal BP, wheels FR, FR brake hydraulic pressure adjusting unit 33, FL brake hydraulic pressure adjusting unit 34, RR brake hydraulic pressure capable of adjusting brake hydraulic pressure supplied to wheel cylinders Wfr, Wfl, Wrr, Wrl arranged in FL, RR, RL, respectively. An adjustment unit 35, an RL brake fluid pressure adjustment unit 36, and the like are provided.

  The high pressure generator 31 includes an electric motor M, a hydraulic pump HP that is driven by the electric motor M and sucks and discharges and raises brake fluid in the reservoir RS, and a check valve CVH on the discharge side of the hydraulic pump HP. And an accumulator Acc for storing brake fluid whose pressure is increased by the hydraulic pump HP.

  The electric motor M is driven when the accumulator hydraulic pressure Pa in the accumulator Acc is equal to or lower than a predetermined lower limit value Pon according to an instruction from the CPU 51 (see FIG. 1) of the motion control device 50, and the accumulator hydraulic pressure Pa is predetermined. Is stopped when the upper limit value Poff (> Pon) is exceeded. Thereby, the accumulator hydraulic pressure Pa is adjusted in principle to “a pressure (high pressure) within a range between the lower limit value Pon and the upper limit value Poff”.

  In addition, a relief valve RV is disposed between the accumulator Acc and the reservoir RS, and when the accumulator hydraulic pressure Pa becomes abnormally higher than the upper limit value Poff, the brake fluid in the accumulator Acc is supplied to the reservoir RS. It is supposed to be returned. As a result, the hydraulic circuit of the high pressure generator 31 is protected.

  The brake fluid pressure generating unit 32 includes a hydro booster HB that responds by the operation of the brake pedal BP, a master cylinder MC connected to the hydro booster HB, and the like. The hydro booster HB assists the operating force of the brake pedal BP at a predetermined rate using the accumulator hydraulic pressure Pa adjusted from the high pressure supplied from the high pressure generating unit 31, and the assisting operating force is applied to the master cylinder. It is transmitted to MC.

  The master cylinder MC generates a master cylinder hydraulic pressure corresponding to the assisted operating force. Further, the hydro booster HB is configured to generate a regulator hydraulic pressure corresponding to the assisted operating force that is substantially the same hydraulic pressure as the master cylinder hydraulic pressure by inputting the master cylinder hydraulic pressure. Since the configuration and operation of the master cylinder MC and the hydro booster HB are well known, detailed description thereof will be omitted here. In this way, the master cylinder MC and the hydro booster HB generate the master cylinder hydraulic pressure and the regulator hydraulic pressure according to the operating force of the brake pedal BP, respectively.

  Between the master cylinder MC and each of the upstream side of the FR brake hydraulic pressure adjusting unit 33 and the upstream side of the FL brake hydraulic pressure adjusting unit 34, a control valve SA1 that is a 2-port 2-position switching type normally open electromagnetic on-off valve is provided. Is intervening. Similarly, between the hydro booster HB and each of the upstream side of the RR brake fluid pressure adjusting unit 35 and the upstream side of the RL brake fluid pressure adjusting unit 36 is a 2-port 2-position switching type normally open electromagnetic on-off valve. A control valve SA2 is interposed.

  The upstream side of the FR brake hydraulic pressure adjusting unit 33 and the upstream side of the FL brake hydraulic pressure adjusting unit 34 are respectively connected to the upstream side of the RR brake hydraulic pressure adjusting unit 35 and the upstream side of the RL brake hydraulic pressure adjusting unit 36. A control valve SA3, which is a 2-port 2-position switching normally closed electromagnetic on-off valve, is interposed in the pipe line. A switching valve STR, which is a 2-port 2-position switching type normally closed electromagnetic on-off valve, is interposed between the high pressure generator 31 and the pipe.

  As a result, when the control valve SA1 and the control valve SA3 (and the switching valve STR) are in a non-excited state, respectively, the upstream part of the FR brake fluid pressure adjusting part 33 and the upstream part of the FL brake fluid pressure adjusting part 34 Cylinder hydraulic pressure is supplied. Further, the accumulator hydraulic pressure Pa generated by the high pressure generator 31 when the control valve SA1, the control valve SA3, and the switching valve STR are in the excited state is supplied.

  Similarly, each of the upstream portion of the RR brake hydraulic pressure adjusting unit 35 and the upstream portion of the RL brake hydraulic pressure adjusting unit 36 includes a regulator hydraulic pressure when the control valve SA2, the control valve SA3, and the switching valve STR are in a non-excited state. Is to be supplied. The accumulator hydraulic pressure Pa is supplied when the control valve SA2, the control valve SA3, and the switching valve STR are in an excited state.

  The FR brake fluid pressure adjusting unit 33 includes a pressure-increasing valve PUfr that is a 2-port 2-position switching type normally-open electromagnetic on-off valve and a pressure-reducing valve PDfr that is a 2-port 2-position switching-type normally-closed electromagnetic on-off valve. Yes. The pressure increasing valve PUfr communicates the upstream portion of the FR brake hydraulic pressure adjusting unit 33 and the wheel cylinder Wfr when in the non-excited state, and the upstream portion of the FR brake hydraulic pressure adjusting unit 33 and the wheel cylinder Wfr when in the excited state. Is designed to block communication. The pressure reducing valve PDfr blocks communication between the wheel cylinder Wfr and the reservoir RS when in the non-excited state, and communicates between the wheel cylinder Wfr and the reservoir RS when in the excited state.

  As a result, the brake fluid pressure (wheel cylinder fluid pressure Pw) in the wheel cylinder Wfr is the upstream portion of the FR brake fluid pressure adjusting unit 33 in the wheel cylinder Wfr when both the pressure increasing valve PUfr and the pressure reducing valve PDfr are in the non-excited state. Is increased (pressure increase control). Further, when the pressure increasing valve PUfr is in an excited state and the pressure reducing valve PDfr is in a non-excited state, the pressure is maintained (holding control) at the current hydraulic pressure regardless of the hydraulic pressure upstream of the FR brake hydraulic pressure adjusting unit 33. It is like that. In addition, when both the pressure increasing valve PUfr and the pressure reducing valve PDfr are in an excited state, the brake fluid in the wheel cylinder Wfr is returned to the reservoir RS so that the pressure is reduced (pressure reduction control).

  In addition, a check valve CV1 that allows only one-way flow of brake fluid from the wheel cylinder Wfr side to the upstream side of the FR brake fluid pressure adjusting unit 33 is disposed in parallel with the pressure increasing valve PUfr. As a result, the wheel cylinder hydraulic pressure Pa in the wheel cylinder Wfr is rapidly reduced when the operated brake pedal BP is released while the control valve SA1 is in the non-excited state.

  Similarly, the FL brake hydraulic pressure adjusting unit 34, the RR brake hydraulic pressure adjusting unit 35, and the RL brake hydraulic pressure adjusting unit 36 are respectively a pressure increasing valve PUfl and a pressure reducing valve PDfl, a pressure increasing valve PUrr and a pressure reducing valve PDrr, and a pressure increasing valve PUrl. The pressure reducing valve PDrl is configured to control and maintain the wheel cylinder Wfl, the wheel cylinder Wrr, and the wheel cylinder hydraulic pressure Pa in the wheel cylinder Wrl by controlling each pressure increasing valve and each pressure reducing valve, respectively. Control and decompression control are possible. In addition, check valves CV2, CV3, and CV4 that can achieve the same function as the check valve CV1 are arranged in parallel in each of the pressure increasing valves PUfl, PUrr, and PUrl.

  Further, the control valve SA2 is provided with a check valve CV5 that allows only one-way flow of the brake fluid from the upstream side to the downstream side in parallel. The control valve SA2 is in an excited state, and is connected to the hydro booster HB. When the communication with each of the RR brake hydraulic pressure adjusting unit 35 and the RL brake hydraulic pressure adjusting unit 36 is cut off, the wheel cylinder hydraulic pressure in the wheel cylinders Wrr and Wrl is operated by operating the brake pedal BP. Pa is increased in pressure.

  The brake fluid pressure control device 30 can supply the brake fluid pressure corresponding to the operating force of the brake pedal BP to each wheel cylinder Wfr, Wfl, Wrr, Wrl when all the solenoid valves SA1 and the like are in a non-excited state. ing. Further, in the non-excited state, for example, by controlling each of the pressure increasing valve PUrr and the pressure reducing valve PDrr, the wheel cylinder is within a range equal to or lower than the brake hydraulic pressure (that is, master cylinder hydraulic pressure) corresponding to the operating force of the brake pedal BP. Only the wheel cylinder hydraulic pressure Pw of Wrr can be increased, held, and reduced.

  Further, the brake hydraulic pressure control device 30 switches, for example, the control valve SA1, the switching valve STR and the pressure increasing valve PUfl to the excited state and the pressure increasing valve in a state where the brake pedal BP is not operated (opened state). By controlling the PUfr and the pressure reducing valve PDfr, respectively, the wheel of the wheel cylinder Wfr is utilized using the accumulator hydraulic pressure Pa generated by the high pressure generator 31 while the wheel cylinder hydraulic pressure Pw of the wheel cylinder Wfl is held at “0”. Only the cylinder hydraulic pressure Pw can be controlled to increase pressure, hold, and reduce pressure within the range of the accumulator hydraulic pressure Pa or less.

  In this way, the brake hydraulic pressure control device 30 independently sets the wheel cylinder hydraulic pressures Pw of the wheel cylinders Wfr, Wfl, Wrr, Wrl of the wheels FR, FL, RR, RL, regardless of the operation of the brake pedal BP. Thus, a predetermined braking force can be applied independently for each wheel. As a result, the brake hydraulic pressure control device 30 can achieve automatic pressurization control, which will be described later, well-known ABS control, and the like according to instructions from the motion control device 50. Each brake fluid pressure adjusting unit 33, 34, 35, 36, the control valves SA1, SA2, and the switching valve STR correspond to the pressure regulating means of the present invention.

  As shown in FIG. 1, the sensor unit 40 includes electromagnetic pickup wheel speed sensors 41fr, 41fl, 41rr, 41rl that output signals having frequencies corresponding to the wheel speeds of the wheels FR, FL, RR, RL, An accelerator opening sensor 42 that detects the operation amount of the accelerator pedal AP operated by the driver and outputs a signal indicating the operation amount of the accelerator pedal AP, and on / off according to the operation / non-operation of the brake pedal BP A brake switch 43 that outputs a signal; a yaw rate sensor 44 that detects a yaw rate of the vehicle and outputs a signal indicating the yaw rate; a lateral acceleration sensor 45 that detects a lateral acceleration of the vehicle and outputs a signal indicating the lateral acceleration; The accumulator hydraulic pressure Pa is detected to output a signal indicating the accumulator hydraulic pressure Pa. 2 (see FIG. 2, corresponding to “detecting means” of the present invention), wheel cylinder hydraulic pressure sensors 47fr, 47fl, 47rr, which detect wheel cylinder hydraulic pressure and output signals indicating wheel cylinder hydraulic pressure, respectively. 47rl (see FIG. 2) and the like.

  The motion control device 50 includes a CPU 51 connected by a bus, a routine (program) executed by the CPU 51, a table (look-up table, map), a ROM 52 in which constants are stored in advance, and the CPU 51 temporarily stores data as necessary. The microcomputer includes a RAM 53 that stores data, a backup RAM 54 that stores data while the power is on, and holds the stored data while the power is shut off, and an interface 55 that includes an AD converter. The interface 55 is connected to the sensor unit 40 and the like, and supplies signals from the sensor unit 40 and the like to the CPU 51, and in response to instructions from the CPU 51, the electromagnetic valves SA1 and the like of the brake fluid pressure control device 30, the electric motor M, and the throttle Drive signals are sent to the valve actuator 22, the fuel injection device 23, and the like.

  Next, referring to the flowchart of FIG. 3 and the time chart of FIG. 4 for the operation when the motion control device 50 executes HDC (Hill Descent Control) that decelerates to a predetermined vehicle speed when the vehicle goes down a hill, for example. I will explain. The motion control device 50 determines whether or not the accumulator hydraulic pressure Pa in the accumulator Acc has become equal to or lower than a predetermined lower limit value Pon (step S1 in FIG. 3). When it is determined that the accumulator hydraulic pressure Pa is equal to or lower than the predetermined lower limit value Pon (Yes in step S1 in FIG. 3, time t1 in FIG. 4A), the drive of the electric motor M is switched from off to on. The hydraulic pump HP is driven (step S2 in FIG. 3, time point t1 in FIG. 4B). As a result, the motor temperature T of the electric motor M rises linearly (time points t1 to t1 in FIG. 4C).

  Then, a timer for measuring the driving time of the electric motor M is turned on (step S3 in FIG. 3), and the motor temperature T of the electric motor M is estimated based on the measured driving time of the electric motor M (step S4 in FIG. 3). ). As an estimation method of the motor temperature T, for example, there is a method of estimating by multiplying a driving time of the electric motor M by a predetermined coefficient. Further, the relationship between the motor temperature T and the driving time may be measured and tabulated in advance, and the table data may be stored in the ROM 52 and read out. Further, a temperature sensor such as a thermistor may be attached to the electric motor M and measured.

  It is determined whether or not the motor temperature T of the electric motor M is equal to or higher than a preset reference temperature Tb (step S5 in FIG. 3). When it is determined that the motor temperature T of the electric motor M is not equal to or higher than the reference temperature Tb (No in step S5 in FIG. 3), the process returns to step S4 to estimate the motor temperature T of the electric motor M described above. Execute. On the other hand, when it is determined that the motor temperature T of the electric motor M is equal to or higher than the reference temperature Tb (Yes in step S5 in FIG. 3, time t2 in FIG. 4C), the pressure gradient of the wheel cylinder hydraulic pressure is decreased. The step-up control is executed (step S6 in FIG. 3, time t2 in FIG. 4D).

  Here, considering the case where the pressure increase control is not executed as in the prior art, the pressure increase gradient of the wheel cylinder hydraulic pressure Pw is not reduced (dotted line from time t2 to time t4 in FIG. 4E), so the brake fluid of the accumulator Acc is not reduced. The amount of consumption is large, and the pressure increase gradient of the accumulator hydraulic pressure Pa remains small (dotted line from time t2 to time t4 in FIG. 4A). Then, when the vehicle is decelerated to a predetermined vehicle speed and the pressure increase of the wheel cylinder hydraulic pressure Pw is stopped and the pressure decrease starts (from time t4 in FIG. 4E), the pressure increase gradient of the accumulator hydraulic pressure Pa increases (see FIG. 4). 4 (a) at time points t4 to t6), the electric motor M stops when the accumulator hydraulic pressure Pa becomes equal to or higher than the predetermined upper limit value Poff (time points t6 in FIGS. 4A and 4B). Therefore, the motor temperature T of the electric motor M continues to rise and may exceed the predetermined dangerous temperature Te (dotted line from time t3 to time t3 in FIG. 4C).

  However, when the pressure increase control is executed to decrease the pressure increase gradient of the wheel cylinder hydraulic pressure Pw as in the present embodiment (solid line from time t2 to t4 in FIG. 4E), the amount of brake fluid consumed by the accumulator Acc. The pressure increase gradient of the accumulator hydraulic pressure Pa becomes large (solid line at time t2 in FIG. 4A). Then, it is determined whether or not the accumulator hydraulic pressure Pa is equal to or higher than a predetermined upper limit value Poff (step S7 in FIG. 3), and when it is determined that the accumulator hydraulic pressure Pa is not equal to or higher than the predetermined upper limit value Poff ( Step S7 in FIG. 3), the process returns to step S6 to continue the boost control.

  On the other hand, when it is determined that the accumulator hydraulic pressure Pa is equal to or higher than the predetermined upper limit value Poff (Yes in step S7 in FIG. 3, time t3 in FIG. 4A), the drive of the electric motor M is switched from on to off. (Step S8 in FIG. 3, time point t3 in FIG. 4B). As a result, the motor temperature T of the electric motor M starts to decrease before reaching the predetermined dangerous temperature Te (time t3 in FIG. 4C). When the vehicle decelerates to a predetermined vehicle speed, the wheel cylinder hydraulic pressure Pw stops increasing and starts decreasing (time t5 in FIG. 4E). Then, it is determined whether or not the motor temperature T of the electric motor M is equal to or lower than the reference temperature Tb (step S9 in FIG. 3), and when it is determined that the motor temperature T of the electric motor M is equal to or lower than the reference temperature Tb ( Step S9 in FIG. 3, Yes, time t7 in FIG. 4C), the boost control is stopped (Step S10 in FIG. 3, time t7 in FIG. 4D), and all the processes are terminated.

  As described above, according to the motion control device 50 of the present embodiment, when the motor temperature T of the electric motor M becomes equal to or higher than the reference temperature Tb, the pressure gradient of the wheel cylinder hydraulic pressure Pw generated by the automatic pressure control is increased. It is decreasing. Thereby, consumption of the accumulator hydraulic pressure Pa can be suppressed, and the driving amount (load or driving time) of the hydraulic pump HP, that is, the electric motor M, can be reduced by the suppression amount. Therefore, overheating of the electric motor M can be prevented, and the durability of the electric motor M can be improved. And the continuous execution time of automatic pressurization control can be kept long, and the reliability of braking can be improved.

  The automatic pressurization control by the motion control device 50 is configured to be executed when the motor temperature T of the electric motor M becomes equal to or higher than the reference temperature Tb, but when the accumulator hydraulic pressure is less than a predetermined hydraulic pressure. It may be configured to be executed, and the operation at that time will be described with reference to the flowchart of FIG. 5 and the time chart of FIG. The motion control device 50 determines whether or not the accumulator hydraulic pressure Pa in the accumulator Acc has become equal to or lower than a predetermined lower limit value Pon (step S11 in FIG. 5). When it is determined that the accumulator hydraulic pressure Pa is equal to or lower than the predetermined lower limit value Pon (Yes in step S11 in FIG. 5, time t1 in FIG. 6A), the drive of the electric motor M is switched from off to on. The hydraulic pump HP is driven (step S12 in FIG. 5, time point t1 in FIG. 6B). Thereby, the motor temperature T of the electric motor M rises linearly from the time point t1 (time points t1 to t1 in FIG. 6C).

  Then, a timer for measuring the drive time of the electric motor M is turned on (step S13 in FIG. 5), and the motor temperature T of the electric motor M is estimated based on the measured drive time of the electric motor M (step S14 in FIG. 5). ). Then, it is determined whether or not the motor temperature T of the electric motor M is equal to or higher than a preset reference temperature Tb (step S15 in FIG. 5), and the motor temperature T of the electric motor M is not equal to or higher than the reference temperature Tb. (No in step S15 in FIG. 5), the process returns to step S14 and the above-described estimation process of the motor temperature T of the electric motor M is executed. On the other hand, when it is determined that the motor temperature T of the electric motor M has become equal to or higher than the reference temperature Tb (Yes in step S15 in FIG. 5, time t2 in FIG. 6C), the pressure gradient of the wheel cylinder hydraulic pressure Pw is decreased. The step-up control is executed (step S16 in FIG. 5, time point t2 in FIG. 6D).

  When the pressure increase control is executed to decrease the pressure increase gradient of the wheel cylinder hydraulic pressure Pw (solid line from time t2 to t4 in FIG. 6E), the amount of brake fluid consumed by the accumulator Acc is small and the pressure increase of the accumulator hydraulic pressure Pa is achieved. The gradient increases (solid line at time t2 in FIG. 6A). Then, it is determined whether or not the accumulator hydraulic pressure Pa is equal to or higher than a predetermined upper limit value Poff (step S17 in FIG. 5), and when it is determined that the accumulator hydraulic pressure Pa is not equal to or higher than the predetermined upper limit value Poff ( Step S17 of FIG. 5), it returns to step S16 and continues execution of pressure | voltage rise control.

  On the other hand, when it is determined that the accumulator hydraulic pressure Pa is equal to or higher than the predetermined upper limit value Poff (Yes in step S17 in FIG. 5, time t3 in FIG. 6A), the drive of the electric motor M is switched from on to off. At the same time, the boost control is stopped (step S18 in FIG. 5, time point t3 in FIGS. 6B and 6D). As a result, the motor temperature T of the electric motor M starts to decrease before reaching the predetermined dangerous temperature Te (time t3 in FIG. 6C). Then, the wheel cylinder hydraulic pressure Pw is increased until the pressure gradient of the wheel cylinder hydraulic pressure Pw is returned to the pressure increasing gradient before the pressure increase control until the vehicle decelerates to a predetermined vehicle speed (time points t3 to t50 in FIG. 6E). When the vehicle decelerates to a predetermined vehicle speed, the wheel cylinder hydraulic pressure Pw stops increasing and starts decreasing (from time t50 in FIG. 6 (e)), and all the processes are terminated.

  As described above, according to the motion control device 50 of the present embodiment, when the accumulator hydraulic pressure Pa is less than the predetermined upper limit value Poff, the pressure gradient of the wheel cylinder hydraulic pressure Pw is reduced. As a result, when the accumulator hydraulic pressure Pa is equal to or higher than the predetermined upper limit value Poff, the normal pressure increase gradient is restored, so the pressure increase time of the wheel cylinder hydraulic pressure Pw is shortened, that is, from time t5 to time t50 in FIG. The braking response can be improved.

  Moreover, in each above-mentioned embodiment, you may comprise so that the fall degree of the pressure | voltage rise gradient of the wheel cylinder hydraulic pressure Pw may be changed according to the raise rate of the motor temperature of the electric motor M. As a result, even if the rising speed of the motor temperature is high, the degree of decrease in the pressure gradient of the wheel cylinder hydraulic pressure Pw can be increased, that is, the pressure increase gradient can be decreased to suppress the consumption of the accumulator hydraulic pressure Pa. Therefore, the drive amount (load and operation time) of the electric motor M can be reduced, and overheating of the electric motor M can be reliably prevented. In addition, as the motor temperature rise rate of the electric motor M decreases, the degree of decrease in the pressure gradient of the wheel cylinder hydraulic pressure is reduced. As a result, the time required for increasing the wheel cylinder hydraulic pressure can be shortened.

  The brake hydraulic pressure control device 30 of the above-described embodiment is a device that uses the hydro booster HB that assists the brake operation by the driver using the accumulator hydraulic pressure Pa. However, the brake hydraulic pressure control device 30 uses the accumulator hydraulic pressure Pa to brake. The present invention can be similarly applied to an apparatus that performs by-wire control. Here, the brake-by-wire control is based on the signal output by the brake operation signal output means that outputs a signal (electrical signal) corresponding to the brake operation by the driver, according to the brake operation by the driver. This is control for generating the wheel cylinder hydraulic pressure Pw. The configuration of the brake fluid pressure control device 30 that performs brake-by-wire control will be described below with reference to the drawings. In addition, the same location as the brake hydraulic pressure control apparatus 30 which uses the hydro booster HB attaches | subjects the same number, and abbreviate | omits detailed description.

  As shown in FIG. 7, the brake hydraulic pressure control device 30 that performs brake-by-wire control has a brake pedal BP that has a hydro booster compared to the brake hydraulic pressure control device 30 that uses the hydro booster HB shown in FIG. A point that is directly connected to the master cylinder MC without passing through the HB, a point that the control valve SA3 is omitted, and a 2 port 2 to a branch line that branches from the middle of a line that connects the master cylinder MC and the control valve SA1. A known stroke simulator SS is provided via a control valve SA4 which is a position switching type normally closed electromagnetic on-off valve, and an operation stroke of the brake pedal BP is detected and a signal indicating the operation stroke is output. The configuration differs in that a stroke sensor 48 is provided. By arranging the stroke simulator SS in this way, when the control valve SA1 and the control valve SA2 (and the switching valve STR) are in the excited state, the control valve SA4 is also in the excited state, so that the brake pedal BP The operation can be secured.

  In a normal state, the brake hydraulic pressure control device 30 that performs this brake-by-wire control constantly maintains the control valves SA1, SA2, SA4 and the switching valve STR in an excited state. The target wheel cylinder hydraulic pressure is determined according to the operation stroke of the brake pedal BP obtained from the stroke sensor 48. Then, by controlling the pressure increasing valve PUfr and the pressure reducing valve PDfr using the accumulator hydraulic pressure Pa, control is performed to make the wheel cylinder hydraulic pressure coincide with the determined target wheel cylinder hydraulic pressure Pw. Yes. In addition, regardless of the operation stroke of the brake pedal BP, the wheel cylinder hydraulic pressure can be freely and independently controlled to achieve automatic pressurization control. On the other hand, when some abnormality occurs, all the solenoid valves SA1 and the like are brought into a non-excited state. Thereby, the wheel cylinder hydraulic pressure Pw according to the operating force itself of the brake pedal BP can be generated, and a fail-safe function for the brake operation can be achieved.

  Also in the brake hydraulic pressure control device 30 that performs the brake-by-wire control with the above-described configuration, it is possible to execute the same boost control as the brake hydraulic pressure control device 30 that uses the hydro booster HB. The effect of.

10: Brake device 20: Driving force transmission mechanism unit 30: Brake hydraulic pressure control device, 31: High pressure generation unit, 32: Brake hydraulic pressure generation unit, 33, 34, 35, 36: Brake hydraulic pressure adjustment unit (pressure adjusting means ), M: electric motor, HP: hydraulic pump, Acc: accumulator, Wfr, Wfl, Wrr, Wrl: wheel cylinder, SA1, SA2: control valve (pressure regulating means), STR: switching valve (pressure regulating means)
40: sensor unit, 46: accumulator hydraulic pressure sensor (detection means)
50: Motion control device (drive control means, automatic pressurization control means, boost control means, motor temperature deriving means)

Claims (4)

Pressure adjusting means (33, 34, 35, 36, SA1, SA2, STR) for adjusting the wheel cylinder hydraulic pressure, which is the brake hydraulic pressure in the wheel cylinder (Wfr, Wfl, Wrr, Wrl) of the wheel brake;
A hydraulic pump (HP);
Drive control means (50) for controlling the electric motor (M) for driving the hydraulic pump;
An accumulator (Acc) for storing brake fluid boosted by driving of the hydraulic pump by the electric motor;
Detecting means (46) for detecting an accumulator fluid pressure which is a pressure of the brake fluid stored in the accumulator;
Automatic pressurization control means (50) for performing automatic pressurization control for generating the wheel cylinder hydraulic pressure independently of a brake operation by a driver by controlling the pressure adjusting means using the accumulator hydraulic pressure; ,
Motor temperature deriving means (50) for deriving the temperature of the electric motor;
A vehicle motion control device comprising pressure increase control means (50) for reducing a pressure increase gradient of the wheel cylinder hydraulic pressure generated by the automatic pressure control when the temperature of the electric motor is equal to or higher than a predetermined temperature.   2. The vehicle motion control device according to claim 1, wherein the pressure increase control means reduces the pressure increase gradient of the wheel cylinder hydraulic pressure when the accumulator hydraulic pressure detected by the detection means is less than a predetermined hydraulic pressure.   3. The vehicle motion control device according to claim 1, wherein the step-up control means changes the degree of decrease in the step-up gradient of the wheel cylinder hydraulic pressure in accordance with the temperature increase rate of the electric motor.   4. The vehicle motion control apparatus according to claim 3, wherein the boost control means reduces the degree of decrease in the pressure gradient of the wheel cylinder hydraulic pressure as the temperature increase rate of the electric motor decreases.

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